Question

When an x-ray beam is scattered off the planes of a crystal,
the scattered beam creates an interference pattern. This phenomenon
is called Bragg scattering. For an observer to measure an
interference maximum, two conditions have to be satisfied:

The angle of incidence has to be equal to the angle of
reflection.

The difference in the beam's path from a source to an
observer for neighboring planes has to be equal to an integer
multiple of the wavelength; that is,

.

The path difference can be determined
from the diagram . The second condition is known as the Bragg
condition.

Part A:

An x-ray beam with wavelength 0.100 is directed at a crystal. As
the angle of incidence increases, you observe the first strong
interference maximum at an angle 22.5. What is the spacing
between the planes of the
crystal?